v5.1: Curved Spaces & Sparse Sets

Major additions:

• Set Intersections & Sparse Distances #100
• Bilinear Forms & Curved Spaces #149, suggested by @guyrosin
• Reduced Memory Consumption #142, suggested by @Charlyo
• Fixing accuracy issues #153, spotted by @cbornet

Minor fixes:

• Extends benchmarks, thanks to @MarkReedZ
• Cleans up CMake, suggested by @rschu1ze
• Exposing f16, i8, b8 to Python buffers in 33f1b13
• Documenting algorithms in 405bef0
• Exposing bf16 to Rust, thanks to @Wyctus

Some crazy findings:

• rsqrt precision on Arm is not documented at all
• rsqrt approximation for double in AVX-512 is only 6x more accurate, than for float
• SciPy raises the wrong errors when overflows - ValueError instead of OverflowError
• SciPy occasionally misuses math.sqrt over numpy.sqrt when dealing with NumPy array
• sqrt in libc is bit-precise